/*
Copyright (c) 2008  Franklin Schmidt <fschmidt@gmail.com>

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
*/

package fschmidt.util.diff;

/*
taken from http://www.incava.org/projects/java-diff/
*/

/**
 * Represents a difference, as used in <code>Diff</code>. A difference consists
 * of two pairs of starting and ending points, each pair representing either the
 * "from" or the "to" collection passed to <code>Diff</code>. If an ending point
 * is -1, then the difference was either a deletion or an addition. For example,
 * if <code>getDeletedEnd()</code> returns -1, then the difference represents an
 * addition.
 */
public class Difference
{
	public static final int NONE = -1;
	
	/**
	 * The point at which the deletion starts.
	 */
	private int delStart = NONE;

	/**
	 * The point at which the deletion ends.
	 */
	private int delEnd = NONE;

	/**
	 * The point at which the addition starts.
	 */
	private int addStart = NONE;

	/**
	 * The point at which the addition ends.
	 */
	private int addEnd = NONE;

	/**
	 * Creates the difference for the given start and end points for the
	 * deletion and addition.
	 */
	public Difference(int delStart, int delEnd, int addStart, int addEnd)
	{
		this.delStart = delStart;
		this.delEnd   = delEnd;
		this.addStart = addStart;
		this.addEnd   = addEnd;
	}

	/**
	 * The point at which the deletion starts, if any. A value equal to
	 * <code>NONE</code> means this is an addition.
	 */
	public int getDeletedStart()
	{
		return delStart;
	}

	/**
	 * The point at which the deletion ends, if any. A value equal to
	 * <code>NONE</code> means this is an addition.
	 */
	public int getDeletedEnd()
	{
		return delEnd;
	}

	/**
	 * The point at which the addition starts, if any. A value equal to
	 * <code>NONE</code> means this must be an addition.
	 */
	public int getAddedStart()
	{
		return addStart;
	}

	/**
	 * The point at which the addition ends, if any. A value equal to
	 * <code>NONE</code> means this must be an addition.
	 */
	public int getAddedEnd()
	{
		return addEnd;
	}

	/**
	 * Sets the point as deleted. The start and end points will be modified to
	 * include the given line.
	 */
	public void setDeleted(int line)
	{
		delStart = Math.min(line, delStart);
		delEnd   = Math.max(line, delEnd);
	}

	/**
	 * Sets the point as added. The start and end points will be modified to
	 * include the given line.
	 */
	public void setAdded(int line)
	{
		addStart = Math.min(line, addStart);
		addEnd   = Math.max(line, addEnd);
	}

	/**
	 * Compares this object to the other for equality. Both objects must be of
	 * type Difference, with the same starting and ending points.
	 */
	public boolean equals(Object obj)
	{
		if (obj instanceof Difference) {
			Difference other = (Difference)obj;

			return (delStart == other.delStart && 
					delEnd   == other.delEnd && 
					addStart == other.addStart && 
					addEnd   == other.addEnd);
		}
		else {
			return false;
		}
	}

	/**
	 * Returns a string representation of this difference.
	 */
	public String toString()
	{
		StringBuffer buf = new StringBuffer();
		buf.append("del: [" + delStart + ", " + delEnd + "]");
		buf.append(" ");
		buf.append("add: [" + addStart + ", " + addEnd + "]");
		return buf.toString();
	}

}
